Where are PHP errors logged to if the error_log directive simply says "error_log"?
error-log, php
Solution
When the value simply says `error_log` (or `error_log = error_log` in your `php.ini` file), that means the errors will be written to a file called `error_log` in the same directory that the error occurs.
So, if you have a file called `index.php` in /home/user/public_html/ that throws an error, the error will be written to: /home/user/public_html/error_log.
If you have file called `resize.php` in /home/user/public_html/admin/images/ that throws an error, then the errors will be written to: /home/user/public_html/admin/images/error_log
Source: Display and log errors for PHP
Problem
I ran `phpinfo()` and the error_log directive simply says `error_log`. What file is that referring to? i.e. what would the full path to the error_log be?